So. California

What to do in your garden in April

Annuals. Replace fading cool-season annuals with heat
lovers. Zinnia Profusion is a favorite with
Sunset's Garden staff because of its six months of bloom.
Besides Cherry, Orange, and White, this year Profusion is available
in Apricot and Fire (scarlet-orange). Other popular choices include
ageratum, coleus, dahlias, marigolds, nicotiana, and phlox.

Container-grown roses. Buying roses in bloom is more
expensive than bare-root, but it allows you to judge flower color,
form, and fragrance. Nurseries are well-stocked with
container-grown plants this month.

Treat for iron deficiency. If camellias, citrus, hibiscus,
and other plants exhibit yellowing leaves with green veins at this
time of year, it's a sign of iron deficiency. Feed plants with a
fertilizer containing chelated iron.

Pests and Diseases

Powdery mildew. A common problem on rose foliage and other
susceptible plants in spring, especially along the coast, this
fungal disease can be difficult to manage. Control it by spraying
leaves with a baking-soda formula: Add 1 tablespoon baking soda and
1 tablespoon canola oil to 1 gallon of water.

Rose pests. Rose slugs ― those caterpillar-like insect
larvae that chomp and tatter rose leaves ― have been a huge
problem in recent years, especially for coastal gardeners. Organic
insecticidal sprays have little effect. Chemical pesticides like
Sevin work, but they kill beneficial insects too. A new option is
Spinosad, a pesticide derived from a soil bacterium. Rose slugs
ingest it, which causes them to stop eating, then starve. Spinosad,
the active ingredient in Monterey Garden Insect Spray (available
from
www.montereylawngarden.com
or 559/499-2100), does not harm most beneficial insects.